1. Field of the Invention
The present disclosure relates to a magnetic resonance imaging (MRI) apparatus for diagnosing various diseases using MRI, and a control method thereof. More particularly, the present disclosure relates to sounds emitted by the MRI during operation.
2. Description of the Related Art
In general, a medical imaging system is an apparatus for providing information about an internal area of a patient as an image. In general, medical imaging systems include, for example, an X-ray machine, an ultrasonic diagnostic instrument, a computer tomography (CT) scanner, a magnetic resonance imaging (MRI) apparatus, etc.
The MRI apparatus holds an important position in the field of medical imaging diagnosis because image-taking conditions are relatively free and can provide excellent detectability and various diagnosis information images with respect to soft tissue.
The MRI causes nuclear magnetic resonance (NMR) in the hydrogen atomic nuclei of the human body using a magnetic field harmless to humans and RF which is non-ionizing radiation, to thus image the densities and physical or chemical characteristics of the atomic nuclei.
In more detail, the MRI apparatus supplies a specific frequency and energy to atomic nuclei in the state in which a constant magnetic field has been applied to the atomic nuclei, to cause the atomic nuclei to release energy, and converts the energy released from the atomic nuclei to signals, thereby diagnosing the inside human body.
When a magnetic field is applied, protons configuring atomic nuclei are arranged in the direction of the magnetic field since they have spin angular momentum and magnetic dipole moment, and the atomic nuclei perform precession with respect to the direction of the magnetic field. The precession causes nuclear magnetic resonance so that an image of the inside human body can be acquired through the nuclear magnetic resonance.
Meanwhile, scanning using a MRI apparatus generally generates a loud noise of about 100 dB. The loud noise that is generated upon scanning using the MRI apparatus is mainly due to the vibration of coils by the Lorentz force that is generated when current is applied to gradient coils in order to form gradient magnetic fields suitable for a specific scanning protocol.
Due to the noise generated by the MRI apparatus, during the scanning period from about 30 minutes to about 1 hour, an operator in an operating room turns down the volume of a speaker connected to a microphone located in a scan room to zero when he or she determines that conversation with a patient is unnecessary so as not to listen to noise captured by the microphone.
However, in the case where the operator turns the speak volume to zero, a problem arises when the patient wants to communicate with the operator because he or she feels discomfort or an emergency situation has occurred, the patient cannot communicate with the operator.